“Stand-up” plastic pouches or bottles for holding liquids and other pourable products are becoming more popular, in part because of the desire to minimize solid waste, in part because of cost, and in part for other reasons. An early stand-up pouch design (U.S. Pat. No. 3,380,646) was devised by the Doyen Brothers in France. That pouch design, including many variants, is still in use today. It is, in fact, the dominant style. The basic Doyen design consists of two flat sheets seamed together along their sides, with a “W” fold running along the bottom. When the pouch is filled, the “W” opens and provides a base on which the pouch can stand. The original Doyen design showed the top being sealed straight across, but subsequent modifications include fitments to allow the pouch to be reclosed after opening.
One difficulty in adding a fitment to a Doyen pouch (and to many other pouch designs as well) is that, according to prior art fitment sealing methods, the fitment must be of the “canoe” style to create a joint that can be reliably sealed. The canoe type of fitment is an attempt to minimize the change in direction of pouch material as it comes into contact with the fitment, and in so doing, improve the integrity of the joint where the two sides of the pouch come together at the fitment. However, even the use of a canoe shaped fitment does not completely solve the difficulties in sealing a fitment into a pouch, and a more reliable sealing means is desirable. The present invention, in one of its aspects, provides such a means.
A “canoe” style fitment is characterized by having a sealing surface that includes relatively sharp changes in direction around the sealing periphery so as to permit the pieces of material being sealed to the fitment to approach the fitment sealing surface (laterally) at relatively shallow angles. Or, put another way, as two webs separate to go around the fitment in opposite directions, the angle of divergence is relatively small. Canoe style fitments are illustrated in, e.g., U.S. Pat. No. 5,660,477, U.S. Pat. No. 4,415,085, and U.S. Pat. No. 4,732,299.
There are at least two other shortcomings of Doyen style pouches with fitments, as compared with the present invention. One is that, because the Doyen body tapers from the bottom to the top, and the present invention has a body that approximates a rectangular parallelepiped, for a given volume contained, the bottle of the present invention requires substantially less material to fabricate. Since material cost is a large part of the cost of flexible packaging, this is a significant factor. Another shortcoming of the Doyen style (and other ungusseted styles), compared to the present invention is that, because the upper body is fabricated from two flat sheets, when the pouch is partly full, the weight of the fitment tends to cause the top of the pouch to fold over, rather than stand erect.
Gusseted bottles (but without fitment) have been made in the past (see U.S. Pat. No. 6,193,416, Kawamata et al., U.S. Pat. No. 6,126,315, Ichikawa et al., and U.S. Pat. No. 5,918,984, LaFleur et al.) Obviously, without a fitment, these prior art containers do not have the utility of the present invention.
U.S. Pat. No. 5,660,477, Ichikawa, discloses a gusseted pouch with a fitment. The fitment shown has flanges protruding from the central section; these create even more sealing problems than a conventional canoe style fitment. Additionally, because of the way the top of the pouch is configured, i.e., the gussets are closed at the top, the fitment weight tends to cause this pouch to fold over when partly full, in a manner very much like a Doyen pouch with fitment.